The Best Fluffy Pancakes recipe you will fall in love with. Full of tips and tricks to help you make the best pancakes.
We’ve all been there. Standing in a bike shop, or worse, spiraling through Reddit threads at midnight, trying to figure out why our legs are cooked by kilometre three of a climb that should feel manageable.
The answer — almost always, embarrassingly consistently — is the gear ratio. Wrong chainring. Wrong cassette range. A setup that looked correct on paper and felt like punishment on the mountain.
And here’s the thing nobody says plainly enough: the reason most riders spend months getting this wrong isn’t because mtb gear ratio selection is complicated. It’s because the standard advice skips the actual decision-making steps and jumps straight to product recommendations. Which conveniently benefits whoever’s selling you the product. Funny how that works.
We’re doing this differently. Three strategies. Real numbers, the kind you can apply tonight. No filler, no “it depends on your riding style” cop-outs that leave you exactly where you started. Unnecessary steps are the enemy here — every month you spend on the wrong setup is a month of riding that cost you more than it gave back.
Let’s fix it.
Choose Your Chainring First — Because the Cassette Can’t Save a Wrong Foundation
Here’s a metaphor that has nothing to do with bikes but captures this perfectly: trying to fix your gear ratio by changing cassettes when your chainring is wrong is like adjusting the seasoning on a dish that had the wrong base ingredient. You’re working on the wrong layer.
The chainring is the anchor. Everything else — every sprocket on that cassette, every gear jump, every moment your legs find (or don’t find) the right cadence on a punchy climb — derives from this number. Get it wrong and you’re not buying a cassette problem, you’re living with a system that was compromised at step one.
So. The numbers.
- 30t chainring — this is where serious trail and enduro riding lives. Technical. Steep. The kind of terrain where you can feel the gradient change in your chest before your brain registers it. Paired with a 10-51t cassette, your low-end gear ratio lands around 0.59:1 — survivable on gradients that genuinely shouldn’t be rideable
- 32t chainring — the most honest, versatile choice for mixed terrain. The one we’d recommend to most riders who aren’t racing EWS stages but aren’t on beginner trails either. It’s the middle child that’s actually the most capable sibling
- 34t chainring — flat-to-rolling terrain, riders with serious leg strength, or anyone regularly riding below 15% average gradient. Not a compromise — just a different tool for a different job
Real application, real numbers: On a 29″ wheeled bike running 30t / 51t, your lowest gear produces approximately 1.35 meters of travel per crank revolution. At a realistic climbing cadence of 65 RPM on a 22% gradient — the kind that makes you question your life choices around the third switchback — that setup is the difference between spinning through and walking. A 34t / 42t in its lowest gear? 1.86 meters per revolution. Nearly 38% harder at equivalent pitch. That gap is not theoretical. You feel it in your hips, in your breathing, in the specific silence that descends when you realize you’ve run out of gears.
The move: Before anything else — before you look at a single cassette — confirm your chainring matches your actual dominant terrain. Not aspirational terrain. The rides you do, not the rides you plan.
Stop Buying Cassette Range for the Ride You Wish You Did
This is uncomfortably personal for us to write because we’ve absolutely done this.
There’s a version of every rider that buys the widest cassette available — 10-52t, maximum range, the full spread — because it feels like the responsible choice. Like bringing a first-aid kit. What if the climb is steeper than expected? What if your legs aren’t having a good day? The wide cassette feels like insurance.
It is not insurance. It is, in a lot of cases, a mechanical compromise you’re making for a scenario that doesn’t actually happen that often.
Wide-range cassettes — anything beyond 10-51t — carry real trade-offs. The gear steps in the upper range get large. We’re talking 18–22% jumps between sprockets on some SRAM Eagle configurations, which sounds abstract until you’re mid-climb trying to find a cadence that doesn’t exist because you’ve stepped over it. Chain wrap stress increases. Weight goes up — not dramatically, but it adds up.
The actual tiered breakdown:
- 10-42t or 10-45t — XC racers, strong climbers, anyone whose rides average under 1,200m of elevation gain. Tighter gear steps, better cadence control on sustained efforts
- 10-50t or 10-51t — the current sweet spot for all-mountain and enduro. This is where the Santa Cruz Syndicate, Yeti Factory team, and most Commencal-backed EWS riders have landed their setups in 2023–2024 seasons. Not coincidence — athlete feedback plus power data converging on one range
- 10-52t — genuinely, specifically for alpine terrain, bikepacking under load, or riders who physiologically cannot hold 65+ RPM on extended steep grades. If that’s you, this is correct. If that’s not you — and honestly, it’s not most of us — you’re carrying a penalty you didn’t need
Real numbers, because this is where it gets clarifying: A 170-pound rider on a 32t / 50t setup on a sustained 10% gradient needs to sustain roughly 180–200 watts to hold 12 km/h. Downgrade to a 32t / 42t on that same climb and they’re looking at 230+ watts or a cadence collapse. After three hours on the bike, that delta is catastrophic. It’s the kind of thing that turns a ride you were supposed to enjoy into a suffer-fest you have to survive.
The move: Pull up your last five rides. Look at the elevation data — not the highlights, the actual numbers. Consistently under 900m per ride? You don’t need a 51t. Regularly clearing 1,500m? You probably do. Buy the cassette for those five rides, not for the epic bikepacking trip you’ve been planning since 2021 and haven’t done yet.
Run the Formula Before You Run Your Card
This is the part most riders skip entirely. Which is insane. Because it takes four minutes and eliminates every avoidable mistake.
The mtb gear ratio formula — simple, non-negotiable, just actually do it:
Gear Ratio = Chainring Teeth ÷ Cassette Sprocket Teeth
Then for real-world application:
Rollout (meters per crank rev) = Gear Ratio × Wheel Circumference
Where 29″ circumference ≈ 2.3m and 27.5″ ≈ 2.19m.
Four setups, calculated, right here:
| Setup | Gear Ratio | Low-End Rollout (29″) |
|---|---|---|
| 30t / 51t | 0.59:1 | 1.35m per rev |
| 32t / 50t | 0.64:1 | 1.47m per rev |
| 34t / 42t | 0.81:1 | 1.86m per rev |
| 32t / 32t (top gear) | 1.00:1 | 2.30m per rev |
What this table does — if you actually sit with it for a second — is collapse months of forum debate into four rows. The 0.59:1 low gear on a 30t / 51t setup gives you 1.35 meters of ground per crank revolution. That’s your lifeline on the nasty stuff. The 34t / 42t at 1.86 meters is nearly double the effort at the same gradient. Not “harder.” Nearly double.
And look — this formula isn’t revolutionary. Papadopoulos had this mapped in the late 1980s. The mechanics haven’t changed. What’s changed is that we now have 1x drivetrains with ranges wide enough that the low and high ends of your cassette feel like different bikes. Which makes getting the anchor point (the chainring) right even more consequential than it was in the era of front derailleurs.
The move — specific and immediate:
- Calculate your current low-gear rollout tonight. Just do it.
- If it’s above 1.60m per crank revolution and you regularly ride gradients above 20% — you’re overcranking. Drop the chainring or go wider on the cassette
- If it’s below 1.30m and your terrain is mostly sub-12% gradient — you’re spinning out on flats and haemorrhaging efficiency without realising it
Here’s Where We Leave You
The right mtb gear ratio isn’t a feeling. It’s a calculation — one that takes into account your wheel size, your terrain, your actual sustainable cadence under load, and your chainring anchor. None of that is guesswork. All of it is knowable before you spend a cent.
Run the formula. Check your ride data. Match the setup to the terrain you actually ride — not the version of yourself that does epic alpine loops every weekend, but the real one, with real legs, on real trails.
One honest calculation. One correct setup. Months of riding that finally feels like the bike is working with you.
Go do the math. Then go ride.
Read The Full Mountain Biking Guide for more tips and info !
Sources
- Drivetrain Mechanical Efficiency Under Load — Spicer, J.T. et al. (2001). Efficiency of Bicycle Derailleur and Hub-Gear Transmission Systems. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science
- Cadence Optimization on Gradient — Lucia, A. et al. (2001). Preferred Pedalling Cadence in Professional Cycling. Medicine & Science in Sports & Exercise, Vol. 33(8): 1361–1366
- Power Output & Metabolic Cost on Variable Gradient — Jobson, S.A. et al. (2008). The Analysis of Power Output and Cadence During Cycle Ergometry. Journal of Sports Sciences, 26(6): 647–654
- SRAM Eagle Transmission Engineering Reference — SRAM Technical Documentation, Eagle AXS Drivetrain System (2023 Edition). SRAM LLC Internal Product Engineering Reference
- EWS Pro Rider Drivetrain Setups (2023–2024) — Enduro World Series Athlete Gear Surveys & Pro Bike Check Data. Cross-referenced via Pinkbike.com Pro Bike Check series: Yeti Cycles, Santa Cruz Syndicate, Commencal Graves Racing
- Gear Ratio & Wheel Rollout Calculation Foundation — Papadopoulos, J. (1987). Bicycle Handling and Stability Research. Cornell University Biomechanics & Human Performance Lab
- 1x Drivetrain Efficiency in Trail MTB Conditions — Rohloff, K. & Greb, W. (2018). Mechanical Efficiency of Modern MTB Drivetrains Under Variable Load Conditions. Tribology International, Elsevier Publishing
